#!/usr/bin/env python 
#-*- coding:utf-8 -*-
'''
simple Factory Method
'''
class Shape(object):
    '''
    父類
    '''
 

    def draw(self):
        raise NotImplementedError
 
class Circle(Shape):
    '''
    Shape子類
    '''
    def draw(self):
        print('draw circle')
 
class Rectangle(Shape):
    '''
    Shape的子類
    '''
    def draw(self):
        print('draw Rectangle')
 
class ShapeFactory(object):
    '''
    工廠模式：暴露給使用者去呼叫的，
    使用者可通過該類進行選擇Shape的子類進行例項化
    
 
'''
    def create(self, shape):
        if shape == 'Circle':
            return Circle()
        elif shape == 'Rectangle':
            return Rectangle()
        else:
            return None
 
fac = ShapeFactory() #例項化工廠類
obj = fac.create('Circle') #例項化Shape的Circle子類
obj.draw()